DepthToSpace

public final class DepthToSpace

DepthToSpace for tensors of type T.

Rearranges data from depth into blocks of spatial data. This is the reverse transformation of SpaceToDepth. More specifically, this op outputs a copy of the input tensor where values from the `depth` dimension are moved in spatial blocks to the `height` and `width` dimensions. The attr `block_size` indicates the input block size and how the data is moved.

* Chunks of data of size `block_size * block_size` from depth are rearranged into non-overlapping blocks of size `block_size x block_size` * The width the output tensor is `input_depth * block_size`, whereas the height is `input_height * block_size`. * The Y, X coordinates within each block of the output image are determined by the high order component of the input channel index. * The depth of the input tensor must be divisible by `block_size * block_size`.

The `data_format` attr specifies the layout of the input and output tensors with the following options: "NHWC": `[ batch, height, width, channels ]` "NCHW": `[ batch, channels, height, width ]` "NCHW_VECT_C": `qint8 [ batch, channels / 4, height, width, 4 ]`

It is useful to consider the operation as transforming a 6-D Tensor. e.g. for data_format = NHWC, Each element in the input tensor can be specified via 6 coordinates, ordered by decreasing memory layout significance as: n,iY,iX,bY,bX,oC (where n=batch index, iX, iY means X or Y coordinates within the input image, bX, bY means coordinates within the output block, oC means output channels). The output would be the input transposed to the following layout: n,iY,bY,iX,bX,oC

This operation is useful for resizing the activations between convolutions (but keeping all data), e.g. instead of pooling. It is also useful for training purely convolutional models.

For example, given an input of shape `[1, 1, 1, 4]`, data_format = "NHWC" and block_size = 2:

x = [[[[1, 2, 3, 4]]]]
 
 
This operation will output a tensor of shape `[1, 2, 2, 1]`:
[[[[1], [2]],
      [[3], [4]]]]
 
Here, the input has a batch of 1 and each batch element has shape `[1, 1, 4]`, the corresponding output will have 2x2 elements and will have a depth of 1 channel (1 = `4 / (block_size * block_size)`). The output element shape is `[2, 2, 1]`.

For an input tensor with larger depth, here of shape `[1, 1, 1, 12]`, e.g.

x = [[[[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]]]]
 
This operation, for block size of 2, will return the following tensor of shape `[1, 2, 2, 3]`
[[[[1, 2, 3], [4, 5, 6]],
      [[7, 8, 9], [10, 11, 12]]]]
 
 
Similarly, for the following input of shape `[1 2 2 4]`, and a block size of 2:
x =  [[[[1, 2, 3, 4],
        [5, 6, 7, 8]],
       [[9, 10, 11, 12],
        [13, 14, 15, 16]]]]
 
the operator will return the following tensor of shape `[1 4 4 1]`:
x = [[[ [1],   [2],  [5],  [6]],
       [ [3],   [4],  [7],  [8]],
       [ [9],  [10], [13],  [14]],
       [ [11], [12], [15],  [16]]]]
 
 

Nested Classes

class DepthToSpace.Options Optional attributes for DepthToSpace

Constants

String OP_NAME The name of this op, as known by TensorFlow core engine

Public Methods

Output <T>
asOutput ()
Returns the symbolic handle of the tensor.
static <T extends TType > DepthToSpace <T>
create ( Scope scope, Operand <T> input, Long blockSize, Options... options)
Factory method to create a class wrapping a new DepthToSpace operation.
static DepthToSpace.Options
dataFormat (String dataFormat)
Output <T>

Inherited Methods

Constants

public static final String OP_NAME

The name of this op, as known by TensorFlow core engine

Constant Value: "DepthToSpace"

Public Methods

public Output <T> asOutput ()

Returns the symbolic handle of the tensor.

Inputs to TensorFlow operations are outputs of another TensorFlow operation. This method is used to obtain a symbolic handle that represents the computation of the input.

public static DepthToSpace <T> create ( Scope scope, Operand <T> input, Long blockSize, Options... options)

Factory method to create a class wrapping a new DepthToSpace operation.

Parameters
scope current scope
blockSize The size of the spatial block, same as in Space2Depth.
options carries optional attributes values
Returns
  • a new instance of DepthToSpace

public static DepthToSpace.Options dataFormat (String dataFormat)

public Output <T> output ()